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