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