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