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