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