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