One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,8)(3,6,4,7)(9,10,16,20)(11,21,14,17)(12,23,22,18)(13,15,19,24)(28,36)(31,38)(35,39)(37,40)(1,2)(3,6)(4,7)(5,8)(9,11,16,14)(10,17,20,21)(12,13,22,19)(15,23,24,18)(25,26)(27,34)(28,31)(29,32)(30,33)(35,40)(36,38)(37,39)(1,3,5,4)(2,6,8,7)(9,12)(10,18)(11,13)(14,19)(15,17)(16,22)(20,23)(21,24)(25,27,30,32)(26,29,33,34)(28,35,36,39)(31,37,38,40)(1,4,5,3)(2,7,8,6)(9,13,16,19)(10,15,20,24)(11,22,14,12)(17,23,21,18)(25,28)(26,31)(27,35)(29,37)(30,36)(32,39)(33,38)(34,40)(9,14,16,11)(10,17,20,21)(12,19,22,13)(15,23,24,18)(25,26)(27,29)(28,31)(30,33)(32,34)(35,37)(36,38)(39,40)(9,15)(10,19)(11,23)(12,17)(13,20)(14,18)(16,24)(21,22)(25,29)(26,32)(27,33)(28,37)(30,34)(31,39)(35,38)(36,40) 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.