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)(11,17)(12,22)(13,15)(14,18)(16,20)(19,21)(23,24)(25,26,31,29)(27,35,38,32)(28,33,37,39)(30,34,36,40)(1,2)(3,6)(4,7)(5,8)(9,11,16,23)(10,17,20,24)(12,21,14,13)(15,22,19,18)(25,27)(26,32)(28,36)(29,35)(30,37)(31,38)(33,34)(39,40)(1,3,5,4)(2,6,8,7)(9,12,16,14)(10,18,20,22)(11,21,23,13)(15,24,19,17)(25,26,31,29)(27,35,38,32)(28,33,37,39)(30,34,36,40)(1,4,5,3)(2,7,8,6)(9,13)(10,19)(11,12)(14,23)(15,20)(16,21)(17,18)(22,24)(25,28,31,37)(26,33,29,39)(27,36,38,30)(32,34,35,40)(9,14,16,12)(10,18,20,22)(11,13,23,21)(15,24,19,17)(25,29,31,26)(27,35,38,32)(28,39,37,33)(30,34,36,40)(9,15,16,19)(10,13,20,21)(11,22,23,18)(12,24,14,17)(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.