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