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