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