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