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