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