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