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