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