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