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