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