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