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