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