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