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