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