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