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