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