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