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