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