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