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