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