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