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