One vertex per element, one color per generator, with an edge from x to x·s.
(9,10,16,19)(11,20,22,17)(12,15,13,23)(14,18,21,24)(25,26,30,34)(27,35,37,31)(28,38,36,32)(29,33,40,39)(1,2)(3,8)(4,6)(5,7)(9,11,16,22)(10,17,19,20)(12,21,13,14)(15,18,23,24)(25,27,30,37)(26,31,34,35)(28,29,36,40)(32,33,38,39)(1,3,5,6)(2,4,7,8)(9,12,16,13)(10,15,19,23)(11,21,22,14)(17,18,20,24)(25,26)(27,31)(28,32)(29,33)(30,34)(35,37)(36,38)(39,40)(1,2)(3,4)(5,7)(6,8)(9,13,16,12)(10,15,19,23)(11,14,22,21)(17,18,20,24)(25,26)(27,35)(28,32)(29,39)(30,34)(31,37)(33,40)(36,38)(1,2)(3,4)(5,7)(6,8)(9,14)(10,18)(11,12)(13,22)(15,20)(16,21)(17,23)(19,24)(25,28)(26,32)(27,29)(30,36)(31,33)(34,38)(35,39)(37,40) involution — undirected(1,4)(2,6)(3,7)(5,8)(9,15)(10,13)(11,18)(12,19)(14,17)(16,23)(20,21)(22,24)(25,29)(26,33)(27,36)(28,37)(30,40)(31,38)(32,35)(34,39) involution — undirectedA Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.