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