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