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