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