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