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