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